Motor driven rotary tooth brush



July 19, 1938. J. MERKEL. JR

MOTOR DRIVEN ROTARYTOO'IIH BRUSH Filed Oct. 18, 1954 Patented July 19, 1938 2,124,145 MOTOR DRIVEN ROTARY TOOTH BRUSH John Merkel, Jr., Evansville, Ind.

Application October 18,

3 Claims.

My invention relates to motor driven tooth brushes and more particularly to the type of tooth brush disclosed and claimed in my earlier United States Letters Patent No. 1,500,410, dated July 8. 1924.

The present invention is directed particularly to a structure employing brushes rotating in opposite directions, say of the intermeshing helical type, wherein the driving mechanism is adapted to be motor driven and embodied in a compact unit between the handle and brush assembly and the motor is preferably embodied in the handle.

One of the essential objects of the invention is to provide a structure of this type which is practical in construction, simple and eflicient in operation.

Another object of the invention is to provide a brush assembly of a construction that may be readily adapted to the driving mechanism in detachable relation so that a number of brush assemblies may be used and each easily fitted to the driving mechanism in proper driving relation to secure proper rotation of the brushes.

A further object of the invention is to provide a motor driven tooth brush having an electrically operated motor uniquely disposed in the handle in the manner permitting a compact and simple arrangement of the parts so that the handle may be suitably gripped by the hand of the user and the tooth brushes easily and efficiently applied to the teeth, whereby the cleansing surface will be brought against the teeth to clean the same thoroughly, and the remaining surface covered by a guard to protect the mouth. The brushes are preferably arranged to provide a brushing motion away from the gums toward the tips of the teeth so that the teeth, gums and crevices will be thoroughly cleaned.

Devices of this type; as heretofore constructed, have not been practical chiefly due to their construction and arrangement of parts. The parts of the device herein disclosed are simple, inexpensive and practically arranged so that the unit may be made in a practical manner at a moderate costand easily used to obtain eiiicient results.

Other objects and advantages of the invention will be apparent from the following detailed description when taken in connection with the accompanying drawing which forms a part hereof.

In the drawing:

Figure 1 is the View partly in elevation and partly in section of a device embodying my invention.

Fig. 2 is a vertical sectional view of the brush assembly taken on line 2-2 of Figure 1.

Fig. 3 is a similar view of another portion of the brush assembly taken on line 3-3 of Figure 1.

Fig. 4 is a similar view taken on line 4--4 of Figure 1.

1934, Serial No. 748,790

Fig. 5 is a similar view through the drive assembly, taken on line 55 of Figure 1.

Fig. 6 is a similar view taken on line 6-6 of Figure 1.

Fig. 7 is a similar view showing the gears of the drive assembly taken on line 11 of Figure 1.

Fig. 8 is a similar vertical sectional view taken on line 8-8 of Figure 1.

Fig. 9 is an enlarged detailed view of the end of the handle to which the drive assembly is attached.

Fig. 10 is a detailed view of the brush assembly.

Fig. 11 is an end view of the handle showing the drive assembly secured thereto, and

Fig. 12 is an end View of the drive-end of the brush assembly.

Referring now to the drawing,a device embodying the invention comprises a handle I of a design that readily fits the hand of a user, a drive assembly 2 attached to one end of this handle I, and a detachable brush assembly 3 which may be readily slipped into position upon the drive assembly 2. Brush assembly 3 comprises oppositely rotating brushes 4 and 5, having their bristles mounted in helical formation upon shafts 6 and I. Each shaft comprises twisted wires which hold the bristles in the usual manner, the outer ends thereof projecting slightly and riding in bearings 8 formed in the outer end of guard 34. The inner ends of the wires forming shafts 6 and I extend inwardly a greater distance to be pressed into quills 9 and I0 journalled in bearings II and I2, respectively, formed in a bearing block I3. Retainer pins 33 may be provided to retain quills 9 and I 0 in proper position in bearings II and I2. Guard 34 is extended rearwardly in the form of a skirt I4 which retains the split bearing block I3 therein by means of rivets l5. If skirt I4 is made of sheet metal, or otherwise, it is apparent that it may be pressed into shape to enclose the bearing block I3 so that rivets I5 passing through the center thereof will suitably hold these parts together. Skirt I4 extends beyond the bearing block I3, however, so that it may be slipped over a reduced shank I6, forming part of the drive assembly 2. Reduced shank I6 is an extension of a housing I I which encases a'pair of spur gears I8 and I9, carried upon shafts 20 and 2| respectively. Shafts 20 and 2I are adapted to be journalled in bearings 22 formed in the reduced shank I6.

The drive assembly further includes an internal gear 23 formed upon spur gear I8. A pinion shaft 24 of an electric motor disposed in handle I extends through anen-d cap 25 to engage the teeth of internal gear 23. Cap 25 is provided with an annular shoulder 26 over which the housing I1 is adapted to fit. A cup-shaped member in the form of a gear retainer 2'! is fitted in housing I! to hold the gears in positions and prevent endwise movement. It will be noted that the interior of housing I1 is cut away at 28 so as to snugly fit the gear retainer 21 into this housing. Bolts 29 passing through the outer face of housing II of drive assembly 2 hold the latter in position, these bolts also passing through the gear retainer 21 and entering the end cap 25 of handle I.

Shafts 20 and 2| of spur gears l8 and I9 are internally cored at their outer ends so that the tips of the quills 9 and I enter the same. The tips of quills 9 and ID are preferably cut away to provide fiat faces while the shafts 20 and 2| of the gears have pins inserted therein to lie against such flat faces of the quills. A positive drive of the quills is thereby obtained as well as an assurance of the proper alignment of the quills when they are inserted in the cored ends of shafts 20 and 2|, whereby to secure the proper rotation of the brushes in opposite direction.

It will be apparent from this description that the parts may be economically made and compactly arranged. Moreover, a practical driving connection is afforded between the electric motor in the handle I and the brushes 4 and 5. No part is of a construction which, when assembled in position, obstructs the convenient use of the tooth brushes when inserted in the mouth for bringing their cleansing surface properly against the gums and teeth.

The brush assembly shown in Figure 10 is adapted to be slipped over the reduced shank I6 of the gear assembly 2. The tips of quills 9 and H] are conveniently brought into proper engagement with the shafts 20 and 2| of gears l8 and. I9 by entering the cored ends thereof, and held in proper driving relation by virtue of the pin arrangement 30. A snap-hump 3| is formed inwardly upon the skirt M to engage in a drill spot 32 in the nose end of the drive assembly 2, heretofore called the reduced shank |B of the drive assembly 2.

More than one tooth brush assembly may be used for each handle unit. These tooth brush assemblies 3 are arranged to slip easily on and off the nose end l6 of the drive assembly 2. It will be noted that each toothbrush assembly comprises parts that are simple and few in number. Moreover, these parts may be easily assembled in a relatively rugged construction that is capable of serving its purpose and of being made at minimum cost. On the other hand, these parts are so constructed that they will efl'iciently operate without the possibility of excessive wear or of soon becoming inoperative. The construction is practical and characterized essentially by its simplicity and practicability.

Likewise, the drive assembly 2 comprises parts that are simple, free from excessive wear or free from becoming out of order, and efficiently transmit the drive from the electric motor in handle to the brushes 4 and 5. Furthermore, these parts assure a ready attachment of the brush assembly 3 so that the brushes 4 and will be driven in opposite directions and the proper rotary relation of the brushes thereby maintained at all times. The gears are simply arranged and mounted in the housing H of the drive assembly 2, requiring only a minimum number of parts and providing a construction that can be simply and inexpensively made, whereby to assure maximum efiicient performance.

Moreover, the drive assembly 2 and its parts permit easy and quick attachment to the head 25 of the handle I. It provides a driving connection from the motor that cannot quickly become inoperative. The skirt construction ll of the tooth brush assembly 3 uniquely permits easy and quick attachment or removal of this assembly from the nose end N5 of the drive assembly 2 so that any number of tooth brush assemblies may be used by the members of one family in connection with a single handle unit I.

Without further elaboration, the foregoing will so fully explain the gist of my invention that others may, by applying current knowledge, readily adopt the same for use under varying conditions of service, without eliminating certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured to me by the following claims:

I claim:

1. In a device of the class described, a pair of oppositely rotating brushes, a handle for said brushes, power driven means for said brushes, said power driven means extending through one end of said handle, spindles for said brushes, a guard extending over all of said brushes excepting their cleansing surfaces, said guard carrying said brushes and said spindles including provisions for journalling said spindles therein as a detachable unitary assembly, and a housing between said handle and said guard, said housing including a driving connection having a pair of intermeshing gears driving said spindles, a pair of shafts carrying said intermeshing gears, an internal gear on one of said shafts, and a pinion meshing with said internal gear, said pinion being driven by said power driven means, and means to detachably connect said shafts with said spindles.

2. In a device of the class described, brushes rotating in opposite directions, power means for driving said brushes, a handle in which said power means may be encased, and a driving connection between said brushes and said power means comprising a housing removably carried by said handle, gear mechanism in said housing, and spindles for said brushes, said spindles being detachably connected to said gear mechanism, a guard device for said brushes provided with a rearwardly extending skirt and having bearings therein for carrying said spindles and said brushes as a removable unitary assembly upon one end of said housing, said housing having a forwardly extending reduced portion provided with bearings therein for said gear mechanism, and means for removably holding said guard skirt upon said reduced portion of said gear housing.

3. In a device of the class described comprising brushes rotating in opposite directions and a guard about and carrying said brushes, power driven means for said brushes and a handle en- :casing the same,,a driving connection and a housing for the same forming a removable intermediate section between said handle and said guard, said driving connection including a gear mechanism having a shaft for each brush, intermeshing gears on said shafts and a driving connec-' 

